1. Field of the Invention
The present invention refers to a testing bench equipped with dynamometric reading capable of measuring the frictional force caused by the warping of the overhead camshaft or misalignment of the headstock bearings, or the lack of frictional force due to low loading of the valve springs. These parameters are easy to diagnose, wherein they show whether there is an excessive clearance of the overhead camshaft support brackets and headstock springs. Moreover, these findings are confirmed through the excessive amount of oil lubricant sprinkling when placed in stepped acceleration rates, which is a phase determined by a table, also created with parameters specifically for this invention.
Such invention facilitates the direct diagnosis of eight possible defects, demonstrated in each phase of the patent. These defects could be detected only after completing the entire headstock mounting in the motor and its installation in the vehicle, or during the course of the warranty period when the defect may have worsened.
This equipment, therefore, which is in the patent application in question, has been especially designed and developed to obtain enormous practicality and to offer great advantages in its use as well as in its manufacture in series.
2. Description of Related Art
It is a well-known fact, for example, that the majority of the modern high-speed rotation internal combustion engines are endowed with grooved belts in its distribution system (crankshaft and overhead camshaft). This grooved belt will have to be substituted normally within a usage range between 30,000 Km (18,634 Mi) and 60,000 Km (37,267 Mi) and, in some models within a maximum of up to 90,000 Km (55,901 Mi), depending on the concept adopted by each engine manufacturer.
Automobile users (a good majority of them) prefer to run the risk because when a grooved belt normally breaks, it damages the inlet and exhaust valves, requiring the necessary removal of the headstock so as to correct it, or the substitution of the parts that were damaged. The necessity to overhaul the headstock can also occur: (1) when the engine is “worn out”; or (2) when there is an excessive thudding of the valve; or (3) through faulty hydraulic tappet; or even yet, (4) through premature abrasion of the cam of the overhead camshaft; (5) when there is already an excessive oil burning caused by the gasket rings of the valve stems and also, by the loss of power; (6) through the wear and tear of the seats, valves and guides; (7) through the removal of the headstock and the shop's necessity to do so; (8) through damages caused by overheating; (9) through the removal of the headstock to allow decarbonization; and so forth.
For all these reasons previously described, the most critical part among the great majority of engines, within the concept of engines, is the upper part, inasmuch as the most durable is the lower part, that is, the block, the crankshaft, the piston, and so forth.
In correcting, doing a check-up or carrying out the substitution for a new headstock with overhead camshaft in the head and for all assembly parts, such as the camshaft, rocker arms, hammers, hydraulic or mechanical tappets, inlet and exhaust valves, gasket rings, springs and keys, all of these require adjustment, calibration and regulation services and care, according to the manual of each engine type and manufacturer.
Such degree of applied technical responsibility would need a machine capable of testing the quality and efficiency of the mounted headstock and its parts. However, another alternative of testing the mounted headstock and its parts does not exist, unless it is installed in a complete engine block and is placed in operation within the vehicle or in a dynamometer. In case malfunction occurs in one of the dozens of parts assembled with the headstock, the solution, most of the time, would be for the mechanic to remove it to perform the same service all over again.
It does not always happen that after the second check-up, the defect or noise is discovered, which causes delay in the delivery of the vehicle to the client. This situation even becomes worse when the engine is imported, since the parts are very expensive and are not always available in the spare parts market, which causes the loss of applied materials, such as: headstock bracket, inlet and exhaust collector, cooling system additive, among others. When dealing with imported parts, the cost of re-work is high, not to speak of the waste of labor applied in the corrections.
We must also remember labor accidents due to burns caused by the dissipation of smoke and evaporation of hot oil lubricants, which exposes the mechanic to unhealthy conditions and, most of all, the loss of time since, in case the task presents any discrepancy, it will be necessary to wait for the temperature to lower, at times this takes hours, so as to carry out a new correction.